Data management system and data management method

ABSTRACT

A file system transfer designation section for transferring the file system matching with file system transfer rules from the first volume of the first storage apparatus to the second volume of the second storage apparatus based on the first file system transfer rules, a file system storage information manager for updating storage information of the file system in accordance with transfer of the file system by the file system transfer designation section, and transmitting the updated file system storage information, and a search information manager for updating search information for searching the files based on a file search request from the client apparatus using the file system storage information sent by the file system storage information manager are provided.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application relates to and claims priority from Japanese PatentApplication No. 2006-247896, filed on Sep. 13, 2006, the entiredisclosure of which is incorporated herein by reference.

BACKGROUND

The present invention relates to a data management system and datamanagement method appropriate for application in data management systemsfor searching files based on requests from, for example, clientapparatus.

In the related art, computer systems are implemented where a clientapparatus, host apparatus and storage apparatus are connected to anetwork so that files managed by the client apparatus are transmittedand received via the host apparatus and the network, and the files arestored on a hard disc within the storage apparatus.

In this kind of computer system, for example, file systems (sets offiles) that are not used often are transferred from so-called high-costhard disc drives within the storage apparatus to so-called low cost discdrives.

Further, with this kind of computer system, for example, file searchapparatus are connected to a network. When there is then a file readrequest instructing the reading of a predetermined file from the clientapparatus, the client apparatus searches for the requested file, and thefile is read out from the storage apparatus to the client apparatus.

However, a search engine for the file search apparatus is usuallydeveloped and put into the form of a product by a dedicated vendor,while software for transferring files of the storage apparatus isdeveloped and put into the form of a product by a storage apparatusvendor. The means that the interface connecting the file searchapparatus and the storage apparatus is not standardized.

Because of this, at the search engine for the file search apparatus,after making a search index table constituting an index in the searchingof a file, at the storage apparatus, in the event of transferring thefile system, it is no longer possible to search files of the file systembased on the search index table and an error therefore results.Therefore, with this kind of computer system, it is necessary to re-makethe search index table in order to search files based on the searchindex table.

In theory, the administrator of the storage apparatus refers to thetransfer history, and takes into consideration an operation where thesearch index table is updated every transferred file system, but thereare cases where several hundred thousand files are stored in one filesystem of the storage apparatus. As the search index table is made infile units, it is not practical for the administrator of the storageapparatus to update the search index table.

As a result, a file management system is proposed in Japanese PatentLaid-open Publication No. 2003-280950 where not used information forfile storage locations, metadata for the files and access priorityinformation is managed, the stored files are accessed and rewriting ofthe files is carried out, where data access are exclusively controlledand the storage locations of files are changed based on storage locationinformation and access priority information for files contained in themetadata.

However, in recent years from the point of view of compliance (actadherence) etc., it is necessary even for files that are usedinfrequently to be held for fixed periods. File systems for files thatare used infrequently are therefore transferred to other storageapparatus and saved.

In the event that this kind of file system is transferred to anotherstorage apparatus, or in the event that a file system is transferred toanother storage apparatus the host apparatus is incapable of mounting,it is not possible to update the storage location information for thefile system, files of the file system cannot be searched, and as aresult it is not possible to read files requested by the clientapparatus.

SUMMARY

In order to take the aforementioned points into consideration, thepresent invention therefore proposes a data management system and datamanagement method with highly reliable data management.

In order to resolve these problems, in one aspect of the presentinvention, a data management system with a host apparatus receivingrequests from client apparatus, first storage apparatus having a firstvolume for storing a file system composed of a set of files, and asecond storage apparatus having a second volume for storing the filesystem sent from the first storage apparatus comprises a file systemtransfer designation section for transferring the file system matchingwith file system migration rules from the first volume of the firststorage apparatus to the second volume of the second storage apparatusbased on the first file system migration rules, a file system storageinformation manager for updating storage information of the file systemin accordance with transfer of the file system by the file systemtransfer designation section, and transmitting the updated file systemstorage information, and a search information manager for updatingsearch information for searching the files based on a file searchrequest from the client apparatus using the file system storageinformation sent by the file system storage information manager.

Further, in an aspect of the present invention, a data management systemwith a host apparatus receiving requests from client apparatus, firststorage apparatus having a first volume for storing a file systemcomposed of a set of files, and a second storage apparatus having asecond volume for storing the file system sent from the first storageapparatus comprises a first step of transferring the file systemmatching with file system migration rules from the first volume of thefirst storage apparatus to the second volume of the second storageapparatus based on the first file system migration rules, a second stepof updating storage information for the file system in accordance withtransfer of the file system of the first step, and transmitting thestored information of the updated file system, and a third step ofupdating the search information for searching the files based on filesearch requests from the client apparatus using file system storageinformation sent in the second step.

Therefore, when a file search request is received from the clientapparatus, a state where search information is not updated iseffectively prevented before it happens, it is possible to search for afile corresponding to the file search request, and as a result, it ispossible to read the file requested by the client apparatus.

According to the present invention, it is possible to implement a datamanagement system and data management method where the reliability offile management is high.

Other aspects and advantages of the invention will be apparent from thefollowing description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block view showing an outline configuration for a datamanagement system of an embodiment;

FIG. 2 is a block view showing an outline configuration for hostapparatus;

FIG. 3 is a block view showing an outline configuration for file systemtransfer apparatus;

FIG. 4 is a block view showing an outline configuration for the firststorage apparatus and the second storage apparatus;

FIG. 5 is conceptual view illustrating an index table;

FIG. 6 is a conceptual view illustrating a reverse index table;

FIG. 7 is a conceptual view illustrating a file system transfermanagement table;

FIG. 8 is a conceptual view illustrating an outline of an operation fora data management system;

FIG. 9 is a flowchart showing an index generation procedure;

FIG. 10 is a flowchart showing a file system transfer startdetermination processing procedure,

FIG. 11 is a flowchart showing a file system transfer processingprocedure;

FIG. 12 is a flowchart showing an index update management processingprocedure;

FIG. 13 is a flowchart showing a file system search handling procedure;

FIG. 14 is a flowchart showing a file system read processing procedure;

FIG. 15 is a flowchart showing a file system mount preparationprocessing procedure; and

FIG. 16 is a block view showing an outline configuration for a datamanagement system of a further embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following is a description with reference to the drawings below of afirst embodiment of the present invention.

FIG. 1 shows a configuration for a data management system 1 of anembodiment of the present invention. The data management system 1 iscomprised of client apparatus 2, host apparatus 3 and file systemtransfer apparatus 4 connected via a LAN (Local Area Network) 5, and thehost apparatus 3, file system transfer apparatus 4, first storageapparatus 6 and second storage apparatus 7 connected via an SAN (StorageArea Network) 8.

The client apparatus 2 is computer apparatus equipped with informationprocessing resources such as a CPU (Central Processing Unit) and memoryetc., such as, for example, a personal computer etc. The clientapparatus 2 are connected to information input apparatus (not shown)such as a keyboard, switches and pointing apparatus, and microphoneetc., and also have information output apparatus (not shown) such asmonitor displays and speakers etc. In this event, the client apparatus 2sends a file read-out request to read out a file to the host apparatus 3based on a file search request for searching files resulting fromdesignation using, for example, keywords etc. and the search results.

FIG. 2 shows a configuration for the host apparatus 3. The hostapparatus 3 is configured from an Ethernet (registered trademark)controller 11 connected to LAN 5 for controlling Ethernet (registeredtrademark) communication, a fiber channel controller 12 for controllingfiber channel communication, an input/output controller 13 forcontrolling information input apparatus and information outputapparatus, a hard disc drive controller 14 for controlling a hard discdrive section 19, a CPU 15 for performing overall control of the hostapparatus 3, and a memory 16 for storing various programs etc, with eachelement of this configuration described above being connected via abridge chip 17 for controlling transfer of files etc.

Further, the hard disc drive section 19 equipped with a number of harddisc drives 18 is connected to the hard disc drive controller 14. Inthis event, some or all of predetermined hard disc drives 18 are used asan index database 20 for storing various tables etc. used in filesearching etc. An index table 21 for storing location information etc.every file, a reverse index table 22 for storing file information etc.containing the keywords every keyword, and a file system transfermanagement table 23 for storing information etc. for before and aftertransfer for file systems for between logical volumes of storageapparatus described later are stored in the index database 20. Adetailed description of the index table 21, reverse index table 22 andfile system transfer management table 23 is given in the following.

Here, a file system is a set of files. In this event, a large number offiles are contained in one file system. A file is digital data and afile system that is this set is also digital data. A logical volume isequipment for storing the file system. In this embodiment, a one to oneconfiguration is adopted where one file system is stored in one logicalvolume, but the present invention is by no means limited in thisrespect, and may also be applied to a configuration where a single filesystem spans a number of logical volumes, or where a single logicalvolume stores a number of file systems.

Further, an application program 31 that is a program for executingvarious processing is also stored in the memory 16 of the host apparatus3. The application program 31 is comprised of an agent 21 that is aprogram executing file search processing and file reading processing, anHTTP/XML stack 33 for executing control based on HTTP/XML (HyperTextTransfer Protocol/eXtensible Markup Language), a TCP/IP stack 34 forexecuting control based on TCP/IP (Transmission ControlProtocol/Internet Protocol), a file system mounting program 35 that is aprogram for managing file systems mounted/un-mounted at the hostapparatus 3, a file system management program 36 that is a program formanaging file systems, an Ethernet (registered trademark) driver 37 thatis a driver for controlling the Ethernet (registered trademark)controller 11, and a fiber channel driver 38 that is a driver forcontrolling the fiber channel controller 12. Here, “mount” refers torecognizing the file system at the host 3 and puts the host apparatus 3into a state enabling the execution of read/write processing.

The agent 32 is comprised of a file search processing program 41, a filereading processing program 42, an indexing program 43, an index updatemanagement program 44, a synchronization management program 45, and adatabase management program 46. A detailed description of each type ofprogram is given in the using the flowchart in the following.

The hardware configuration of this host apparatus 3 may be implementedthrough various forms of general purpose computers (personal computers),workstations, and mainframes, etc. The index table 21, reverse indextable 22 and file system transfer management table 23 may be stored inthe memory 16.

FIG. 3 shows a configuration for the file system transfer apparatus 4.The file system transfer apparatus 4 adopts the same configuration asfor the host apparatus 3, with the exception that the various programsand information etc. stored in the memory 56 and the hard disc drivesection 59 are different. Namely, the file system transfer apparatus 4is implemented using a general purpose computer (personal computer),etc. The file system transfer apparatus 4 is comprised of an Ethernet(registered trademark) controller 51, a fiber channel controller 52, aninput/output controller 53, a hard disc drive controller 54, a CPU 55,and a memory 56 connected via a bridge 57.

A hard disc drive section 59 equipped with a plurality of hard discdrives 58 is connected to the hard disc controller 54. In this event,migration rules 61 and a file system transfer management table 62 arestored in a predetermined hard disc drive 58.

Fixed rules for transferring a file system, such as, for example, “inthe event that any files of the file system have not been subjected toreading or writing processing for a predetermined period, transfer thisfile system from the first storage apparatus 6 to the second storageapparatus 7”, and “in the event that the final update time where thefrequency of read/write processing during the preceding three months islow at 20% of the file systems mounted at the host apparatus 3 ischecked and one month or more has passed since the final update time,this file system is transferred from the first storage apparatus 6 tothe second storage apparatus 7”, are described in the migration rules61. The configuration of the file system transfer management table 62 isthe same as the file system transfer management table 23 describedabove.

Further, a file system transfer manager 71 that is a program forexecuting file system transfer processing etc., a HTTP/XML stack 72, aTCP/IP stack 73, a file system management program 74, an Ethernet(registered trademark) driver 75 and a fiber channel driver 76 arestored in the memory 16 of the file system transfer apparatus 4. Thefile system management program 74 differs from the file system mountingprogram 35 in managing the file systems that are mounted/un-mounted atall of the host apparatus 3.

The file system transfer manager 71 is comprised of a file systemtransfer initiating program 81, a synchronization management program 82,a file system transfer notification program 83, a file system transferprogram 84, and a file system mounting preparation program 85. Adetailed description of each type of program is given in the using theflowchart in the following.

The hardware configuration of this file system transfer apparatus 4 maybe implemented by personal computers etc. in various forms. Themigration rules 61 and the file system transfer management table 62 mayalso be stored in the memory 56.

FIG. 4 shows a configuration for the first storage apparatus 6 and thesecond storage apparatus 7. The first storage apparatus 6 is comprisedof storage controller 91A and a storage section 92A. The storagecontroller 91A is configured in such a manner that a front endcontroller 101A for controlling fiber channel communication connected toSAN8, CPU 102A for overall control of the first storage apparatus 6, aback end controller 106A connected to the cache memory 104A fortemporarily storing transmitted and received files and storage section92A, for controlling communication with the storage section 92A, areconnected with each element of the configuration described above, andare connected via data transfer controller 103A for controlling thetransfer of data. Further, a local memory 105A for storing programs andtables necessary for controlling the first storage apparatus 6 andinformation etc. is connected to the CPU 102A. Moreover, the storagesection 92A is equipped with a plurality of hard disc drives 111A.

The CPU 102A is capable of controlling the plurality of hard disc drives111A using RAID levels (for example, RAID0, 1, 5 etc.) defined in theso-called RAID system. The RAID system manages a plurality of hard discdrives 111A as a single RAID group. A plurality of logical volumes 112Aare then defined in access units by the host apparatus 3 on the RAIDgroup. A LUN (Logical Unit Number) is allocated to the respectivelogical volumes 112A.

The hard disc drive 111A is, for example, a storage device such as an FC(Fibre Channel) disc drive, a SATA (Serial Advanced TechnologyAttachment) disc drive, a PATA (Parallel Advanced Technology Attachment)disc drive, a FATA (Fibre Attached Technology Adapted) disc drive, anSAS (Serial Attached SCSI) disc drive, or a SCSI (Small Computer SystemInterface) disc drive, etc.

The second storage apparatus 7 has the same configuration as the firststorage apparatus 6 described above, with each element of theconfiguration of the second storage apparatus 7 being given the samenumerals for the same portions as the configuration elements of thefirst storage apparatus 6, with suffix “A” being substituted with suffix“B”. At the data management system 1, from the point of view that thesecond storage system 7 is a storage system for archiving use, the discdrive 111A of the first storage system 6 is configured from, forexample, a so-called high-cost hard disc drive such as a SCSI (SmallComputer System Interface) disc drive etc., and the drive 111B of thesecond storage system 7 is configured from a so-called low-cost harddisc drive such as, for example, a SATA (Serial AT Attachment) discdrive or optical disc drive, etc.

Next, a description is given of the configuration of the index table 21,reverse index table 22, and file system transfer management table 23.

FIG. 5 is a view showing a configuration for the index table 21. Theindex table 21 stores an index record number 121 for identifying theindex record, a host apparatus identifier 122 for identifying the hostapparatus 3 that made the file, a file system identifier 123 foridentifying the file system for the logical volume storing the file, apath name 124 for a path indicating the location of the file system, afile name 125 for the file, attributes 126 comprised of a file updatedate and access priority control information etc., and a keyword list127 composed of keywords for the file, every index record. There arealso cases where the host apparatus identifier 122, file systemidentifier 123, path name 124 and file name 125 are collectivelyreferred to as location information 128. The host apparatus identifier122 is to take into consideration the case where a plurality of hostapparatus exist, where a host apparatus 3 mounted to after a logicalvolume goes temporarily offline (described later) and goes online onceagain (described later) is different to the host apparatus 3 that firstmade the file.

FIG. 6 is a view showing a configuration for the reverse index table 22.The reverse index table 22 is a table adopting, for example, a B-Tree(Balanced tree) algorithm, that is capable of searching using an indextree (index tree) of this structure at high-speed. This reverse indextable 22 is capable of searching every keyword 131. The reverse indextable 22 stores an index record number 132 and attributes 133 for a filehaving this keyword 131 every reverse record for the keyword 131. Inthis event, the index record number 132 of the reverse index table 22corresponds to the index record number 121 of the index table 21. Thereverse index table 22 is then capable of searching the index recordnumber 121 of the index table 21 from the keyword 131.

FIG. 7 shows a configuration for the file system transfer managementtable 23. The file system transfer management table 23 stores a filesystem identifier 141, a file system state 142 indicating the storagestate of the file system, an original host apparatus identifier 143 foridentifying the host apparatus 3 that made the file first, an originalstorage apparatus identifier 144 for identifying the storage apparatusthat stored the file system before transfer, an original logical volumeidentifier 145 for identifying the logical volume that stored the filesystem before transfer, a current host apparatus identifier 146 foridentifying a host apparatus 3 mounting a file system currentlycontaining the file, a current storage apparatus identifier 147 foridentifying the storage apparatus currently storing the file system, andan original logical volume identifier 148 for identifying the logicalvolume currently storing the file system, every mapping record.

It is necessary to update the file system state 142, the original hostapparatus identifier 143, the original storage apparatus identifier 144,the original logical volume identifier 145, the current host apparatusidentifier 146, the current storage apparatus identifier 147, and theoriginal logical volume identifier 148 as a result of transfer of thefile system. Further, there are cases where the file system state 142,the original host apparatus identifier 143, the original storageapparatus identifier 144, the original logical volume identifier 145,the current host apparatus identifier 146, the current storage apparatusidentifier 147, and the original logical volume identifier 148 arecollectively referred to as file system transfer information 149.

At the file system state 142, for example, “primary storage” isdescribed for the case where the file system is stored in the firststorage apparatus 6, “secondary storage” is described for the case wherethe file system is stored in the second storage apparatus 6, “writeenable” is described in the case where the file system can be writtento, “write inhibit” is described for the case where it is not possibleto write to the file system, “online” is described for the case wherethe file system is mounted at the host apparatus 3, and “offline” isdescribed for the case where the file system is not mounted at the hostapparatus 3. A sequential description is given of a state transition forthe storage state of the file system. Further, “online” indicates thestate where the file system is mounted at the host apparatus 3, andoffline indicates the state where the file system is not mounted at thehost apparatus 3.

Further, the file system transfer management table 62 stores a filesystem identifier 151, a file system state 152, an original hostidentifier 153, an original storage apparatus identifier 154, anoriginal logical volume identifier 155, a current host apparatusidentifier 156, a current storage apparatus identifier 157, and anoriginal logical volume identifier 158, every mapping record. Moreover,there are cases where the file system state 152, the original hostidentifier 153, the original storage apparatus identifier 154, theoriginal logical volume identifier 155, the current host apparatusidentifier 156, the current storage apparatus identifier 157, and theoriginal logical volume identifier 158 are collectively referred to asfile system transfer information 159.

FIG. 8 shows an outline of the operation of the data management system1. With the data management system 1, at the file system transferapparatus 4, the file system is transferred from the logical volume 112Aof the first storage apparatus 6 to the logical volume 112B of thesecond storage apparatus 7 based on the file system transfer managementtable 61 (A1), the file system transfer update information 159 of thefile system transfer management table 62 of the file system transfermanagement apparatus 4 updated in accordance with the transfer of thefile system is sent to the host apparatus 3 (A2), and the file systemtransfer information 159 of the file system transfer management table 23of the index database 20 of the host apparatus 3 is updated (A3).

Specifically, describing an outline of an operation of the datamanagement system 1, the host apparatus 3 stores the file in the logicalvolume 112A of the first storage apparatus 6 by sending the file sentfrom the client apparatus 2 to the first storage apparatus 6. The hostapparatus 3 reads out and analyzes a file sent from the client apparatus2, or made or updated at the host apparatus 3 from the first storageapparatus 6 by periodically executing the agent 32, and makes locationinformation 128, attributes 126, or a keyword list 127. The hostapparatus 3 updates the index table 21 and the reverse index table 22 ofthe index database 20 using the produced location information 128,attributes 126, and keyword list 127.

Here, the file system transfer apparatus 4 transfers the file system 161from the logical volume 112A of the first storage apparatus 6 to thelogical volume 112B of the second storage apparatus 7 by executing thefile system transfer manager 71 at a predetermined timing, and sending afile system transfer request for the file system 161 to the firststorage apparatus 6 and the second storage apparatus 7 at apredetermined period where reading and writing processing is not takingplace in accordance with the migration rules 61.

When transfer of the file system 161 is complete, the file systemtransfer apparatus 4 updates the file system transfer information 159 ofthe file system transfer management table 62. The file system transferapparatus 4 then sends the file system transfer information 159 of theupdated file system transfer management table 62 to the host apparatus 3together with the file system transfer notification.

The host apparatus 3 then updates the file system transfer information149 of the file system transfer management table 23 of the indexdatabase 20 using the file system transfer update information 159 of thetransmitted file system transfer management table 62.

As a result, at the data management system 1, when a file search requestis received from the client apparatus 2, the state where the file systemmanagement table 23 is not updated is effectively prevented before ithappens, it is possible to search for the file corresponding to the filesearch request, and as a result, it is possible to read the filerequested by the client apparatus 2.

Next, a description is given of index generation occurring at the hostapparatus 3. FIG. 9 is a flowchart showing a specific processingprocedure of the CPU 15 of the host apparatus 3 relating to the indexgeneration occurring at this host apparatus 3.

When the host apparatus 3 is started up, the CPU 15 of the hostapparatus 3 waits in a standby mode for an activation start time of theindex generation to elapse in accordance with the index generationprocedure RT1 shown in FIG. 9 by executing the index generation program43 making each type of index table. The activation start time is set toa fixed time interval that is comparatively short that is, for example apredetermined certain time of one day (once every 24 hours), etc.

When the activation start time for the index generation elapses (S1:YES), the CPU 15 of the host apparatus 3 checks the file systems mountedat the host apparatus 3 by executing the file system management program36, and selects one file system of the file systems (S2). The CPU 15 ofthe host apparatus 3 then selects one file of the selected file system(S3). The CPU 15 of the host apparatus 3 then checks whether theselected file is a file that is newly added or whether or not the fileis an updated file (S4).

In the event that the selected file is not a newly added file and is notan updated file (S4: NO), the CPU 15 of the host apparatus 3 proceeds tostep S7. On the other hand, in the event that the selected file is anewly added file or an updated file (S4: NO), the CPU 15 of the hostapparatus 3 reads out the file and analyzes the content of the file(S5).

The CPU 15 of the host apparatus 3 then produces the locationinformation 128, attributes 126 and keyword list 127 based on the fileanalysis results by executing the database management program 46, andupdates the index table 21 and/or the reverse index table 22 of theindex database 20 using the produced location information 128,attributes 126, and keyword list 127 (S6).

The CPU 15 of the host apparatus 3 then checks whether or not all of thefiles of the selected file system have been selected (S7). In the eventthat all of the files for the selected file system have not beenselected (S7: NO), the CPU 15 of the host apparatus 3 selects the nextfile of the selected file system (S8). After this, step S4 for checkingwhether or not the selected file is a newly added file or an updatedfile is returned to, and the same processing is then repeated (S4 toS8).

On the other hand, in the event that all of the files for the selectedfile system are selected (S7: YES), the CPU 15 of the host apparatus 3checks whether or not all of the file systems mounted at the hostapparatus 3 have been selected (S9). In the event that all of the filesystems mounted at the host apparatus have not been selected (S9: NO),the CPU 15 of the host apparatus 3 selects the next file system (S10).After this, step S3 for selecting one file of the selected file systemsis returned to and the same processing is repeated (S3 to S10).

On the other hand, in the event that all of the file systems mounted atthe host apparatus 3 have been selected (S9: YES), the CPU 15 of thehost apparatus 3 returns to a standby mode awaiting the elapsing of theactivation start time for the index generation (S1), and after this, thesame processing is repeated (S1 to S10).

Next a description is given of file system transfer start determinationprocessing occurring at the file system transfer apparatus 4. FIG. 10 isa flowchart showing a detailed processing procedure of the CPU 55 of thefile system transfer apparatus 4 relating to the file system transferstart determination processing occurring at this file system transferapparatus 4.

When the file system transfer apparatus 4 starts up, the CPU 55 of thefile system transfer apparatus 4 waits in standby mode for theactivation start time of the file system transfer start determinationprocess to elapse in accordance with file system transfer startdetermination processing procedure RT2 shown in FIG. 10 by executing thefile system transfer start determination processing program 81 fordetermining whether or not transfer of the file system has started(S11). The activation start time is set to a fixed time interval that iscomparatively long that is, for example, a predetermined certain time ofa certain day of one month.

When the activation start time for the index generation elapses (S11:YES), the CPU 55 of the file system transfer apparatus 4 checks the filesystems mounted at a predetermined host apparatus 3 by executing thefile system management program 74, and selects one file system of thefile systems (S12). The CPU 55 of the file system transfer apparatus 4then checks whether or not the selected file system matches with themigration rules 61.

In the event that the selected file system does not match with themigration rules 61 (S13: NO), the CPU 55 of the file system transferapparatus 4 proceeds to step S14 On the other hand, in the event thatthe selected file system matches with the migration rules 61 (S13: YES),the CPU 55 of the file system transfer apparatus 4 executes file systemtransfer notification processing (RT3) by executing the file systemtransfer notification program 83.

Here, a description is given of file system transfer processingoccurring at the file system transfer apparatus 4. FIG. 11 is aflowchart showing a detailed processing procedure of the CPU 55 of thefile system transfer apparatus 4 relating to the file system transferprocessing occurring at this file system transfer apparatus 4.

When the selected file system matches with the migration rules 61, theCPU 55 of the file system transfer apparatus 4 transfers the selectedfile system from the logical volume 112A of the first storage apparatus6 to the logical volume 112B of the second storage apparatus 7 inaccordance with the file system transfer processing procedure RT3 shownin FIG. 11 by executing the file system transfer processing procedure 84for transferring the file systems (S21).

Specifically, the CPU 55 of the file system transfer apparatus 4 sendsthe file system transfer request for the selected file system to thefirst storage apparatus 6 and the second storage apparatus 7. When afile system transfer request transmitted from the file system transferapparatus 4 is received, the CPU 102A of the first storage apparatus 6sends a file system stored in the logical volume 112A corresponding tothe file system transfer request to the second storage apparatus 7. TheCPU 102B of the second storage apparatus 7 stores the file system sentfrom the first storage apparatus 6 in the logical volume 112B. Whentransfer of the file system is complete, the second storage apparatus 7sends the file system transfer completion notification to the filesystem transfer apparatus 4 and the first storage system 6. When a filesystem transfer completion notification is received from the secondstorage apparatus 7, the first storage apparatus 6 deletes thetransmitted file system from the logical volume 112A.

When file system transfer completion notification is received from thesecond storage apparatus 7, the CPU 55 of the file system transferapparatus 4 updates the file system transfer management table 62 (S22).

Specifically, at the mapping record corresponding to the file systemidentifier 151 of the file transfer management table 62 of thetransferred file system, for example, the CPU 55 of the file systemtransfer apparatus 4 changes the file system state 152 from “primarystorage”, “write enabled”, and “online” to “secondary storage”, “writeinhibit”, and “online”, changes the original storage apparatusidentifier 154 and the original logical volume identifier 155 to theidentifiers for the first storage apparatus 6 and the logical volume112A stored by the transferred file system, and changes the currentstorage apparatus identifier 157 and the current logical volumeidentifier 158 to the identifiers for the second storage apparatus 7 andthe logical volume 112B storing the transferred file system.

The CPU 55 of the file system transfer apparatus 4 then makes a filesystem transfer notification by executing the synchronization managementprogram 82 that is a program controlling communication andsynchronization with other apparatus such as the host apparatus 3, andsends the file system transfer notification and the file system transferinformation 159 for the updated file transfer management table 62 to thehost apparatus 3 corresponding to the current host apparatus identifier156 of the mapping record (S23).

The CPU 55 of the file system transfer apparatus 4 then ends the filesystem transfer processing procedure RT3 (S24) after this, and proceedsto step S14 of the file system transfer start determination processingprocedure RT2 shown in FIG. 10.

The CPU 55 of the file system transfer apparatus 4 then checks whetheror not all of the file systems mounted on the host apparatus 3 have beenselected (S14). In the event that all of the file systems mounted at thehost apparatus 3 are not selected (S14: NO), the CPU 55 of the filesystem transfer apparatus 4 selects the next file system (S10). Afterthis, step S13 for checking whether or not the selected file systemmatches with the migration rules 61 is returned to, and the sameprocessing is then repeated (S13 to S15, RT3).

On the other hand, in the event that all of the file systems mounted atthe host apparatus 3 have been selected (S14: YES), the CPU 15 of thehost apparatus 3 returns to a standby mode awaiting the elapsing of theactivation start time for the file system start determination processing(S11), and after this, the same processing is repeated (S11 to S15).

Next, a description is given of index update management processingoccurring at the host apparatus 3. FIG. 12 is a flowchart showing aspecific processing procedure of the CPU 15 of the host apparatus 3relating to the index update management processing occurring at thishost apparatus 3.

When the host apparatus 3 starts up, the CPU 15 of the host apparatus 3waits in a standby mode to receive file system transfer notification andfile system transfer information 159 of the system transfer managementtable 62 from the file system transfer apparatus 4 in accordance withthe index update management processing procedure RT4 shown in FIG. 12 byexecuting the index update management processing program 44 for managingand updating the various index tables (S31).

When the synchronization management program 82 is executed at the filesystem transfer apparatus 4, when the synchronization management program45 is then executed and file system transfer notification and filesystem transfer information 159 for the system transfer management table62 is then received from the file system transfer apparatus 4 (S31:YES), the CPU 15 of the host apparatus 3 updates the file systemtransfer management table 23 of the index database 20 in the same way asupdating the file system transfer management table 62 by executing thedatabase management program 46,managing the index database 20 using thefile system transfer information 159 of the file system transfermanagement table 62 (S32).

In this event, it is possible to perform update processing for the indexdatabase 20 at a substantially higher speed at the CPU 15 of the hostapparatus 3 without updating the index records of the index table 21constituted by an enormous number for managing each file by putting theindex table to one side, managing the transfer of file systems atmapping records of the file system transfer management table 23 of asmall total number of files, and managing logical volumes where thesefiles are stored.

The CPU 15 of the host apparatus 3 then returns to a standby modeawaiting the receipt of file system transfer notification and filesystem transfer information 159 for the system transfer management table62 from the file system transfer apparatus 4 (S31), and the same processis then repeated after this (S31 and S32).

Next, a description is given of file search processing occurring at thehost apparatus 3. FIG. 13 is a flowchart showing a specific processingprocedure of the CPU 15 of the host apparatus 3 relating to the indexupdate management processing occurring at this host apparatus 3.

When the host apparatus 3 is started up, the CPU 15 of the hostapparatus 3 goes into standby mode awaiting the receipt of a filetransfer request from the client apparatus 2 in accordance with the filesearch processing procedure RT5 shown in FIG. 13 by executing the filesearch processing program 41 for searching files (S41). Conditions forsearching for files such as, for example, “files containing both keyword“budget” and keyword “IT” and searching of all of the files made duringthe past three years” etc. are described in the file search request.

Upon receiving the file search request from the client apparatus 2 (S41:YES), the CPU 15 of the host apparatus 3 searches the index table 21,reverse index table 22 and file system transfer management table 23 ofthe index database 20 by executing the database management program 46,and sends the file search request to another host apparatus 3 byexecuting the synchronization management program 45 (S42).

Specifically, in the event that the files are searched using thekeywords, the CPU 15 of the host apparatus 3 obtains the index recordnumber 132 of the keywords 131 by searching for keywords 131 of thereverse index table 22. Next, because the index record number 132corresponds to the index record number 121, the CPU 15 of the hostapparatus 3 obtains the file system identifier 123 of the index recordnumber 121 from this index record number 121. The CPU 15 of the hostapparatus 3 the obtains the current storage apparatus identifier 147 andthe logical volume identifier 148 from this file system identifier 141because the file system identifier 123 corresponds to the file systemidentifier 141.

Further, in the case of searching files using these attributes, the CPU15 of the host apparatus 3 is capable of obtaining the file name 125 andfile system identifier 123 of the attributes 126 by searching theattributes 126 of the index table 21. As in the case described above,the CPU 15 of the host apparatus 3 then obtains the current storageapparatus identifier 147 and the logical volume identifier 148 from thisfile system identifier 141 because the file system identifier 123corresponds to the file system identifier 141.

The CPU 15 of the host apparatus 3 is therefore able to recognize whichlogical volume of which storage apparatus the file system correspondingto the file search request of the client apparatus 2 is currently storedin by searching the index table 21, reverse index table 22, and filesystem transfer management table 23 of the index database 20 asdescribed above.

When the synchronization management program 82 is executed at the hostapparatus 3 receiving a file search request from the client apparatus 2,the synchronization management program 45 is executed, and the filesearch request is received from the host apparatus 3, as in the casedescribed above, by executing the database management program 46, theCPU 15 of the other host apparatus 3 searches the index table 21, thereverse index table 22 and the file system transfer management table 23of the index database 20, and sends the file name 125, current storageapparatus identifier 147 and current logical volume identifier 148subject to the file search request from the client apparatus 2 to thehost apparatus 3 that received the file search request as a file searchresults report.

Continuing on, the CPU 15 of the host apparatus 3 ends searching of theindex table 21, reverse index table 22 and file system transfermanagement table 23 of the index database 20, and awaits the receipt ofthe file search results report from all of the other host apparatus 3 instandby mode (S43).

When searching of the index table 21, reverse index table 22, and filesystem transfer management table 23 of the index database 20 is completeand file search results report is received from all of the other hostapparatus 3 (S43: YES), the CPU 15 of the host apparatus 3 makes a filesearch results synopsis list corresponding to the file search requestfrom the client apparatus 2 based on the file search results at the hostapparatus 3 and the file search results report from all of the otherhost apparatus 3, and sends the file search results synopsis list to theclient apparatus 2 (S44).

The CPU 15 of the host apparatus 3 then returns to standby mode wherereceipt of a file search request from the client apparatus 2 is againawaited (S41), and then repeats the same processing (S41 to S44).

Next, a description is given of file read processing occurring at thehost apparatus 3. FIG. 14 is a flowchart showing a specific processingprocedure of the CPU 15 of the host apparatus 3 relating to the fileread processing occurring at this host apparatus 3.

When the host apparatus 3 is started up, the CPU 15 of the hostapparatus 3 goes into standby mode awaiting the receipt of a file readrequest from the client apparatus 2 in accordance with the file readprocessing procedure RT6 shown in FIG. 14 by executing the file readingprocessing program 42 for reading files (S51). The client apparatus 2then refers to the file search results synopsis list sent from the hostapparatus 3, and in the event that a file the user of the clientapparatus 2 wishes to read exists, a file read request for the file issent to the host apparatus 3.

When a file read request is received from the client apparatus 2 (S51:YES), the CPU 15 of the host apparatus 3 refers to the file searchresults at the host apparatus 3 and the current storage apparatusidentifier 147 and the current logical volume identifier 148 in the filesearch results report from the all of the other host apparatus 3, andchecks whether or not the file corresponding to the file read request isstored in the second storage apparatus 7 (S52).

In the event that a file corresponding to the file read request is notstored in the second storage apparatus 7 (S52: NO), the CPU 15 of thehost apparatus 3 proceeds to step S57. On the other hand, in the eventthat the file corresponding to the file read request is stored in thesecond storage apparatus 7 (S52: YES), the CPU 15 of the host apparatus3 sends a mount request for the file system of the file corresponding tothe file read request to the file system transfer apparatus 4 byexecuting the synchronization management program 45 (S53).

Continuing on, the CPU 15 of the host apparatus 3 awaits the receipt ofa mount preparation completion notification from the file systemtransfer apparatus 4 in standby mode (S54). When the synchronizationmanagement program 82 is executed at the file system transfer apparatus4, the synchronization management program 45 is executed, and mountpreparation completion notification and file system transfer information159 of the system transfer management table 62 is received (S54: YES),by executing the file system mounting program 35, the CPU 15 of the hostapparatus 3 refers to the current storage apparatus identifier 157 andthe current logical volume identifier 158 at the file system transferinformation 159 of the system transfer management table 62, and mountsthe file system corresponding to the file read request at the hostapparatus 3 (S55).

The CPU 15 of the host apparatus 3 updates the file system transfermanagement table 23 (S56) in the same way as the updating occurring atthe file system transfer management table 62 described in the followingby executing the database management program 46 and using the filesystem transfer information 159 for the file system transfer managementtable 62.

The CPU 15 of the host apparatus 3 then reads out a file correspondingto the file read request from the file system (S57). The CPU 15 of thehost apparatus 3 sends the file to the client apparatus 2 thattransmitted the file read request (S58). The CPU 15 of the hostapparatus 3 then returns to standby mode where receipt of a file readrequest from the client apparatus 2 is again awaited (S51), and thenrepeats the same processing (S51 to S58).

Next a description is given of file system mount preparation processingoccurring at the file system transfer apparatus 4. FIG. 15 is aflowchart showing a detailed processing procedure of the CPU 55 of thefile system transfer apparatus 4 relating to the file system mountpreparation processing occurring at this file system transfer apparatus4.

The CPU 55 of the file system transfer apparatus 4 awaits the receipt ofa mount request from the host apparatus 3 in standby mode (S61). Whenthe CPU 55 of the file system transfer apparatus 4 receives a mountrequest from the host apparatus 3 (S61: YES), the file system of thefile corresponding to the file read request checks whether or not directmounting from the second storage apparatus 7 to the host apparatus 3 ispossible (S62).

Specifically, the CPU 55 of the file system transfer apparatus 4 has atable (not shown) within memory 56 describing in advance whether directmounting of host apparatus 3 such as, for example, storage apparatus ofa VDL (Virtual Disk Library) or SATA disc drive etc. can be directlymounted, or whether direct mounting is possible at host apparatus 3 suchas a tape library etc. for, for example, all of the second storageapparatus 7 that are connected, and checks whether or not directmounting is possible in accordance with the table.

In the event that it is possible for the file system corresponding tothe file read request to be directly mounted at the host apparatus 3from the second storage apparatus 7 (S62: YES), the CPU 55 of the filesystem transfer apparatus 4 proceeds to step 64. On the other hand, inthe event that it is not possible to directly mount the file system forthe file corresponding to the file read request from the second storageapparatus 7 to the host apparatus 3 (S62: NO), the CPU 55 of the filesystem transfer apparatus 4 transfers the file system for the filecorresponding to the file read request from the logical volume 112B ofthe second storage apparatus 7 to the logical volume 112A of the firststorage apparatus 6 (S63).

Specifically, the CPU 55 of the file system transfer apparatus 4 sendsthe file system transfer request of the file system of the filecorresponding to the file read request to the first storage apparatus 6and the second storage apparatus 7. When a file system transfer requesttransmitted from the file system transfer apparatus 4 is received, theCPU 102B of the second storage apparatus 6 sends a file system stored inthe logical volume 112B corresponding to the file system transferrequest to the first storage apparatus 6. The CPU 102A of the firststorage apparatus 6 then stores the file system sent from the secondstorage apparatus 7 in the logical volume 112A. When transfer of thefile system is complete, the first storage apparatus 6 sends the filesystem transfer completion report to the file system transfer apparatus4 and the first storage system 6.

When file system transfer completion notification is received from thefirst storage apparatus 6, the CPU 55 of the file system transferapparatus 4 updates the file system transfer management table 62 (S64).

Specifically, in the event that, for example, it is possible to directlymount the file system for the file corresponding to the file readrequest from the second storage apparatus 7 to the host apparatus 3, theCPU 55 of the file system transfer apparatus 4 changes the file systemstate 152 from “secondary storage”, “write inhibit” and “offline” to“secondary storage”, “write permit”, and “online” at the mapping recordcorresponding to the file system identifier 151 of the file transfermanagement table 62 of the file system.

Further, in the event that, for example, the file system of the filecorresponding to the file read request cannot be directly mounted fromthe second storage apparatus 7 to the host apparatus 3, the CPU 55 ofthe file system transfer apparatus 4 changes the file system state 152from “secondary storage”, “write inhibit”, and “offline” to “primarystorage”, “write inhibit”, and “online” at the mapping recordcorresponding to the file system identifier 151 of the file transfermanagement table 62 of the file system, changes the original storageapparatus identifier 154 and the original logical volume identifier 155to the identifiers of the second storage apparatus 7 and the logicalvolume 112B that stored the transferred file, and changes the currentstorage apparatus identifier 157 and current logical volume identifier158 to the identifiers of the first storage apparatus 6 and the logicalvolume 112A that stored the transferred file system.

The CPU 55 of the file system transfer apparatus 4 makes file systemmount preparation completion notification by executing thesynchronization management program 82, and sends the file system mountpreparation completion notification and the file system transferinformation 159 for the updated file transfer management table 62 to thehost apparatus 3 corresponding to the current host apparatus identifier156 of the mapping code (S65).

After this, the CPU 55 of the file system transfer apparatus 4 returnsto a standby mode so as to await the receipt of a mount request from thehost apparatus 3 (S61), and the same processing is then repeatedthereafter (S61 to S65).

Rather than transferring the file system corresponding to the file readrequest from the logical volume 112B of the second storage apparatus 7to the logical volume 112A of the first storage apparatus 6 (S63), theCPU 55 of the file system transfer apparatus 4 can also operate so as toduplicate the file system to the logical volume 112A of the firststorage apparatus 6.

In this case, the CPU 55 of the file system transfer apparatus 4, forexample, stores a table (not shown) housing a file system identifier 151for the duplicated file system in memory 56, and stores a file systemidentifier 153 for the duplicated file system in the table when the filesystem is duplicated at the logical volume 112A of the first storageapparatus 6.

After this, in the event that the CPU 55 of the file system transferapparatus 4 transfers the files again from the logical volume 112A tothe logical volume 112B of the second storage apparatus 7 in accordancewith the file system transfer processing procedure RT3 shown in FIG. 11described above (S21), the file system is already stored in the logicalvolume 112B of the second storage apparatus 7, and the same results asfor transferring the system file from the logical volume 112A of thefirst storage apparatus 6 to the logical volume 112B of the secondstorage apparatus 7 can be obtained by deleting the file system from thelogical volume 112A of the first storage apparatus 6.

Namely, the file system selected as described above is transferred fromthe logical volume 112A of the first storage apparatus 6 to the logicalvolume 112B of the second storage apparatus 7 (S21), the table storingthe file system identifier 151 of the duplicated file system issearched, and in the event that the file system identifier 151 for thefile system selected in the manner described above is stored on thetable, the CPU 55 of the file system transfer apparatus 4 deletes thefile system from the logical volume 112A of the first storage apparatus6, transfer from the logical volume 112A of the first storage apparatus6 to the logical volume 112B of the second storage apparatus 7 can becompleted, and the speed of file system transfer processing can beincreased dramatically.

At this time, at the mapping record corresponding to the file systemidentifier 151 of the file transfer management table 62 of thetransferred file system, for example, the CPU 55 of the file systemtransfer apparatus 4 changes the file system state 152 from “primarystorage”, “write enabled”, and “online” to “secondary storage”, “writeinhibited”, and “online”, and switches over the original storageapparatus identifier 154 and the original logical volume identifier 155with the current storage apparatus identifier 157 and the currentlogical volume identifier 158.

In this way, at the data management system 1, at the file systemtransfer apparatus 4, the file system is transferred from the logicalvolume 112A of the first storage apparatus 6 to the logical volume 112Bof the second storage apparatus 7 based on the file system transfermanagement table 61, the file system transfer update information 159 ofthe file system transfer management table 62 of the file system transfermanagement apparatus 4 updated in accordance with the transfer of thefile system is sent to the host apparatus 3, and the file systemtransfer information 159 of the file system transfer management table 23of the index database 20 of the host apparatus 3 is updated (A3).

Therefore, at the data management system 1, when a file search requestis received from the client apparatus 2, the state where the file systemmanagement table 23 is not updated is effectively prevented before ithappens, it is possible to search for the file corresponding to the filesearch request, and as a result, it is possible to read the filerequested by the client apparatus 2. It is therefore possible to providea data management system with highly convenient file management and lowoperating costs, having both high availability and reliability.

Further, with the data management system 1, at the file system transferapparatus 4, it is determined whether or not the file system for thefile corresponding to the file read request is capable of being mounteddirectly from the second storage apparatus 7 to the host apparatus 3. Inthe event that direct mounting is not possible, the file system for thefile corresponding to the file read request is transferred from thelogical volume 112B of the second storage apparatus 7 to the logicalvolume 112A of the first storage apparatus 6 so as to make mountingpossible. This means that it is possible to prevent a situation where afile of a file system cannot be read even in the event of transfer fromthe first storage apparatus 6 to the second storage apparatus 7 and itis possible to read the file requested by the client apparatus 2.

Further, with the data management system 1, at the file system transferapparatus 4, by duplicating the file system of the file corresponding tothe file read request from the logical volume 112B of the second storageapparatus 7 to the logical volume 112A of the first storage apparatus 6,when the file system is then again transferred from the logical volume112A of the first storage apparatus 6 to the logical volume 112B of thesecond storage apparatus 7, it is possible to obtain the same results asfor transferring from the logical volume 112A of the first storageapparatus 6 to the logical volume 112B of the second storage apparatus 7by deleting the file system from the logical volume 112A of the firststorage apparatus 6.

In this embodiment, a description is given of the case where each hostapparatus 3 implements an index producing function and an index updatingmanagement function, but the present invention is by no means limited inthis respect, and, for example, as shown in FIG. 16, an index server 171may be provided, with the agent 32 then being divided into an agent 172having a file search function and a file read function and an agent 173having an index producing function and an index update managementfunction. An index producing function and index update managementfunction implemented with each host apparatus 3 distributed may then beimplemented focused on the index server 171.

Further, in this embodiment, a description is given of the case wherethe file system transfer apparatus 4 is provided, and the file systemtransfer apparatus 4 implements each of the functions relating to thefile system transfer described above, but the present invention is by nomeans limited in this respect, and, for example, as shown in FIG. 16, itis also possible for the first storage apparatus 6 to have the functionrelating to transfer of the file systems in the possession of the filesystem transfer apparatus 4, and to implement each of the functionsrelating to file system transfer the file system transfer apparatus 4 isin possession of at the first storage apparatus 6.

The present invention is therefore broadly applicable to data managementsystems that search files based on requests from client apparatus andread out the files from client apparatus.

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

1. A data management system with a host apparatus receiving requestsfrom client apparatus, a first storage apparatus having a first volumefor storing a file system composed of a set of files, and a secondstorage apparatus having a second volume for storing the file systemsent from the first storage apparatus, comprising: a file systemtransfer designation section for transferring the file system matchingwith file system migration rules from the first volume of the firststorage apparatus to the second volume of the second storage apparatusbased on the first file system migration rules; a file system storageinformation manager for updating storage information of the file systemin accordance with transfer of the file system by the file systemtransfer designation section, and transmitting the updated file systemstorage information; and a search information manager for updatingsearch information for searching the files based on a file searchrequest from the client apparatus using the file system storageinformation sent by the file system storage information manager.
 2. Thedata management system according to claim 1, further comprising: a mountdetermination section for determining whether or not a file system for afile corresponding to a file read request from the client apparatus iscapable of being directly mounted from the second storage apparatus tothe host apparatus, wherein the file system transfer section: transfersthe file system from the second volume of the second storage apparatusto the first volume of the first-storage apparatus that is capable ofmounting the file system at the host apparatus in the event that themount determination section determines that the file system can not bedirectly mounted.
 3. The data management system according to claim 2,the host apparatus further comprising: a mount management section formanaging mounting and un-mounting of the file system; and the mountmanagement section: directly mounting the file system for the filecorresponding to the file read request from the client apparatus fromthe second storage apparatus in the event that the mount determinationsection determines that direct mounting of the file system is possible.4. The data management system according to claim 2, wherein the filesystem transfer section: duplicates the file system from the secondvolume of the second storage apparatus to the first volume of the firststorage apparatus that is capable of mounting the file system at thehost apparatus in the event that the mount determination sectiondetermines that the file system can not be directly mounted.
 5. The datamanagement system according to claim 1, wherein the search informationcomprises: information containing host apparatus, file system,attributes and a keyword list every file, information containing fileand attributes every keyword, and information containing the hostapparatus, storage apparatus and volume for before transfer, the hostapparatus, storage apparatus and volume for after transfer, and thestorage state of the file system, every file system.
 6. The datamanagement system according to claim 1, the storage information furthercomprising: information containing the host apparatus, storage apparatusand volume for before transfer, the host apparatus, storage apparatusand volume for after transfer, and the storage state of the file system,every file system.
 7. The data management system according to claim 1,wherein the file system transfer designation section and the file systemstorage information manager are provided at the file system transferapparatus, and the search information manager comprises: a plurality ofthe host apparatus.
 8. The data management system according to claim 1,wherein the search information manager is provided at an index server,and the file system transfer designation section and the file systemstorage information manager are provided at the first storage apparatus.9. A data management method for a data management system with a hostapparatus receiving requests from client apparatus, first storageapparatus having a first volume for storing a file system composed of aset of files, and a second storage apparatus having a second volume forstoring the file system sent from the first storage apparatus,comprising: a first step of transferring the file system matching withfile system migration rules from the first volume of the first storageapparatus to the second volume of the second storage apparatus based onthe first file system migration rules; a second step of updating storageinformation for the file system in accordance with transfer of the filesystem of the first step, and transmitting the stored information of theupdated file system; and a third step of updating the search informationfor searching the files based on file search requests from the clientapparatus using file system storage information sent in the second step.10. The data management method according to claim 9, further comprising:a fourth step of determining whether or not a file system for a filecorresponding to a file read request from the client apparatus iscapable of being directly mounted from the second storage apparatus tothe host apparatus; and a fifth step of transferring the file systemfrom the second volume of the second storage apparatus to the firstvolume of the first storage apparatus that is capable of mounting thefile system at the host apparatus, in the event that it is determined inthe fourth step that the file system cannot be directly mounted.
 11. Thedata management method according to claim 10, further comprising: asixth step of managing mounting and un-mounting of the file system;wherein, in the sixth step, a file system for a file corresponding to afile read request from the client apparatus is directly mounted from thesecond storage apparatus in the event that it is determined that thefile system can be directly mounted in the fourth step.
 12. The datamanagement method according to claim 10, wherein in the fifth step: thefile system is transferred from the second volume of the second storageapparatus to the first volume of the first storage apparatus that iscapable of mounting the file system at the host apparatus, in the eventthat it is determined in the fourth step that the file system cannot bedirectly mounted.
 13. The data management method according to claim 9,wherein the search information comprises: information containing hostapparatus, file system, attributes and a keyword list every file,information containing file and attributes every keyword, andinformation containing the host apparatus, storage apparatus and volumefor before transfer, the host apparatus, storage apparatus and volumefor after transfer, and the storage state of the file system, every filesystem.
 14. The data management method according to claim 9, the storageinformation further comprising: information containing the hostapparatus, storage apparatus and volume for before transfer, the hostapparatus, storage apparatus and volume for after transfer, and thestorage state of the file system, every file system.
 15. The datamanagement method according to claim 9, wherein the first step and thesecond step: are carried out at the file system transfer apparatus, andthe third step: is carried out at the corresponding host apparatus ofthe plurality of host apparatus.
 16. The data management methodaccording to claim 9, wherein the first step and the second step: arecarried out at the first storage apparatus, and the third step: iscarried out focusing on the index server.